SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a89319c70fe4f58275c2441ee2a2345ce8fdca7b1c90b58d0647ba8dd4570279' 
  AND token = 'xSR1CnqcS2VtQqQli8A3KcGFYVhEX+QG30SvkOxzhJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}